


Hypnoctober Day 14

by birdginia



Series: Hypnoctober 2018 [14]
Category: Assassination Classroom
Genre: Consentacles, M/M, Sex Pollen, Sexual Fantasy, Teacher-Student Relationship, Tentacle Sex, Trans Male Character, Triple Penetration, teacher/student fantasy
Language: English
Status: Completed
Published: 2018-10-19
Updated: 2018-10-19
Packaged: 2019-08-04 08:21:13
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 1,596
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16343261
Author URL: https://archiveofourown.org/users/birdginia/pseuds/birdginia
Summary: (prompt - tentacles)Nagisa has a list, both in his notebook and on a public document in Ritsu’s files for anyone to reference in their own assassination plans, of not only Koro-sensei’s weaknesses, but also his demonstrated abilities.In another notebook, a smaller one that Nagisa keeps in a drawer at home, he has another list.





	Hypnoctober Day 14

Nagisa has a list, both in his notebook and on a public document in Ritsu’s files for anyone to reference in their own assassination plans, of not only Koro-sensei’s weaknesses, but also his demonstrated abilities. His speed, his reflexes, and his intelligence, of course, but also specific instances of his powers in action, like the clones, the sticky net, even the exact magnification of his zoom eyes.

In another notebook, a smaller one that Nagisa keeps in a drawer at home, he has another list. This one contains as yet unproven theories, both those that have some measure of evidence to back them up and those that emphatically do not. After all, he keeps most of his abilities a secret until their use is absolutely necessary, so he could have plenty of tricks up his sleeve that he won’t pull out until specific parameters are met.

A few of these theories include:

**Theory #1: Speed boost**

It’s possible that, similar to when humans experience a rush of adrenaline and are able to perform superhuman feats under certain circumstances, Koro-sensei could move even faster than Mach 20. There is currently no evidence of this, as even at his angriest he has never broken that limit (at least, not without bragging about it, which is a more accurate speedometer than anything Nagisa can think of), but it’s something to keep in mind for contingency plans if an assassination is dependent on his currently known speed cap of Mach 20.

**Theory #2: Acidic mucus**

Koro-sensei’s mucus has already been observed to be both sticky and slippery at different times for different purposes, even though it always comes from the same sources in his body. Therefore, it’s possible that Koro-sensei can consciously change the viscosity of his mucus, so it’s also possible that he could change other properties, such as pH. This could result in acidic mucus that could be applied to restraints or other parts of a trap, rendering him even more difficult to keep contained.

**Theory #3: Mental override**

Koro-sensei is a superhuman creature with all sorts of unknown abilities that are only seen in science fiction, so it isn’t out of the question to consider that he could control the minds of others. He might be able to call for help from the animals that live in the forest, commanding an army of rabbits or birds to chew through ropes, or pick locks, or just distract his students long enough to avoid assassination.

Or—and this is only a theory, obviously—he might be able to affect the minds of his students directly. Obviously, Nagisa knows, he wouldn’t do this unless there were a very, very good reason to. Sensei wouldn’t want to influence the class’s assassination plans or affect their studying in that sort of way.

But, _theoretically_ , if Sensei were able to do this, it would be possible for him to stop any face-to-face assassination with nothing but his winning smile, or his voice, or maybe he could make his skin flash colors in such a way as to overload the human brain, make Nagisa—or, of course, any other student, obviously—fall to his knees, eyes rolling back, jaw slackened, hand loosening on his knife, completely helpless to do anything, much less complete an assassination.

**Theory #4: Mind-altering mucus**

It’s also possible, though unproven, that Koro-sensei could affect the chemical content of his mucus so that it might affect the human body in ways akin to any number of drugs. This is along the same lines as the theory of general mental override, but if the control is limited to his mucus, different strategies would be required to avoid it. It might be topical, meaning that any direct skin-to-tentacle contact would inflict its effects. Or it might be absorbed through mucous membranes, meaning the tentacle would have to make contact with the eye, nose, ears, mouth, or—well. The mucous membranes.

Koro-sensei would easily be able to make that contact. He’s constantly putting his supportive, teacherly tentacles on them, patting their shoulders, brushing their hair, and it would be so simple for him to slip a tentacle into Nagisa’s—anyone’s—mouth. _If_ he were to do that—and, again, Nagisa can’t think of any reason he would, barring an attempt to foil an assassination—it could cause a potential assassin to become momentarily distracted, or suppress their willingness to kill immediately. It could even shift their focus to something else, such as a heightened sense of their own body, skin suddenly so sensitive that the air around them would feel like a tangible presence, clothes suddenly too itchy and too overwhelming to wear in this state.

Nagisa knows that Koro-sensei understands his own strength, and would know just what his abilities do to someone, so if— _if_ —something like that were to occur, he would definitely know that that student wouldn’t be feeling well, and that under those kinds of effects, a student very suddenly wanting to strip out of their uncomfortable clothes would be a perfectly sensible solution.

He probably would have taken the tentacle out of Nagisa’s mouth by then, but he might not have, giving Nagisa a few moments to feel the weight of it, the texture. Maybe the longer Nagisa held the tentacle in his mouth, the more mucus would enter his system, dizzying him more and more with each passing second, until he was squirming on top of Koro-sensei, knife slipping from between his fingers and falling to the side.

With both his hands free, Nagisa would be able to undo his tie and unbutton his vest, but getting rid of his uniform pants would be a little more difficult—at least, in this scenario, where he’s been straddling Koro-sensei for the best angle to take a knife to him. But Koro-sensei is kind and understanding, and Nagisa is sure he’d let him take the time to take them off and then settle back into his position.

Of course, it’s also entirely possible that the mucus could have non-aphrodisiacal effects, and this is just one theory out of many, but it’s one Nagisa has been considering for a while, so he has a lot of the details sorted out. Like the way Koro-sensei would nervously tell him not to be afraid, that this is perfectly natural for boys his age, and that the effects should wear off in a few hours, so Sensei is going to go find Nagisa some fresh spring water from the nearest faraway country.

But Nagisa would stop him, would grab the tentacle that had just been halfway down his throat and take it back into his mouth, sucking and licking and watching for Koro-sensei’s reactions. Maybe Sensei wouldn’t visibly respond, but maybe his face would tint pink, or his mouth open slightly with a soft sound. Nagisa would grab for another tentacle with his other hand, squeezing gently, rubbing his thumb along the strange, alien skin.

Maybe—and naturally this is just one possibility—the cure for these effects would actually be to keep ingesting more mucus until exposure hits a certain threshold, at which point the body begins to develop a tolerance to it. Koro-sensei would explain that to Nagisa, and Nagisa would suddenly understand the implications—that the quickest way to get through this would be to take as much as possible, through every outlet available. 

Koro-sensei would object, of course, but Nagisa’s needy little cries and the look of pleading in his eyes would convince kind, understanding Sensei otherwise. 

He’d be so careful, at first, one tentacle pressing gentle, soothing circles into Nagisa’s inner thigh before carefully reaching to touch him between his legs. Nagisa would be so wet already that the first tendril would go in easy, and a shudder would ripple through him as the effects of the mucus intensified, making him clench down around the tentacle and moan around the other one in his mouth.

The second pseudo-finger would spread him open further, and the bulb at the base of Sensei’s hand would take some time to fit, even with Nagisa pushing against him wantonly, but when it finally filled him up, Nagisa just knows it would press right against where he’d want it, leaving him shaking all over, gasping through his nose.

But of course it wouldn’t be enough. And Koro-sensei would know this, so he’d start prodding carefully, so carefully, at Nagisa’s ass, the mucus enough lubrication to allow him to slowly ease inside of him. And by then, Koro-sensei might have given up on trying to protect his precious student’s virtue, so instead of pretending that this is only to get things over with as fast as possible, he’d be trying to make Nagisa feel good. One tentacle would be rubbing quick circles against Nagisa’s clit, while two more would be sliding across his nipples, occasionally offering a light pinch.

It would take a long time for the mucus to run the course of its effects. Nagisa would be so full for so long, completely surrounded by Koro-sensei, and once he’d come, Koro-sensei would praise him, tell him he’s been such a good boy, that he takes it so well, that he wants Nagisa to be the one to kill him so much, and Nagisa would feel so good from the praise alone that he’d come again, and again, as Koro-sensei worked him over, giving him everything he has, until Nagisa would be completely wrecked, exhausted and sore and thoroughly satisfied to the limits of his imagination.

But, of course, this is only a theory.

**Author's Note:**

> shiota nagisa is a self-indulgent bitch and so am i sorry about it
> 
> my twitter is over at [@Slotheyyyyy](https://twitter.com/Slotheyyyyy). check out my very important thoughts and opinions on fucking, and @ me with any of yours!


End file.
